twistedneck
Automotive
- Dec 13, 2005
- 81
Dear eng-tips crew, need your help figuring out requirements for fatigue on this stabilizer bar.
Life 100,000 - i get that.
Random sample, min six parts - OK got that.
Here's where i get lost
"The test requirement is for Pu = 50% (actually P sub u double dot), and permissible standard deviation s log <= 0.20"
Anyone know what P sub u double dot is?
For the standard deviation requirement, I tried a simple log of my usual standard deviation and its about 4 (log of 10,000 = 4). Not even close to the 0.2 required. so i must be doing soemthing wrong, maybe 's' is a constant? everything is in German so its difficult to follow.
I'm used to B10C90 etc..
Help appriciated - thank you,
Jeff
Life 100,000 - i get that.
Random sample, min six parts - OK got that.
Here's where i get lost
"The test requirement is for Pu = 50% (actually P sub u double dot), and permissible standard deviation s log <= 0.20"
Anyone know what P sub u double dot is?
For the standard deviation requirement, I tried a simple log of my usual standard deviation and its about 4 (log of 10,000 = 4). Not even close to the 0.2 required. so i must be doing soemthing wrong, maybe 's' is a constant? everything is in German so its difficult to follow.
I'm used to B10C90 etc..
Help appriciated - thank you,
Jeff
